The present invention relates to a device which is provided for an interchangeable lens barrel whose focalization operation is automatically controlled through the camera body.
In order to automatically carry out lens focalization a variety of devices have been proposed in the art which, for instance, are provided either outside of the lens barrel or integral with the camera. However, the conventional devices have not been found suitable for cameras which use interchangeable lenses as they require a relatively great focalizing force and accordingly are bulky in construction. Additionally the rotational resistance force involved in the focalizing operation is not uniform among different lenses.
In order to alleviate these problems an object of the invention is to provide a lens barrel automatic focalization device in which a drive force transferring means which receives a focalizing operation force from a camera body is disposed at a position in the mount adapted to permit a lens barrel to engage with the camera body. It is desired that the device only minimally interfere with the optical paths of the optical system and that the rotational resistance force which is generated in the focalizing operation and is variable with different lenses is controlled so as to make uniform the response time of the focalizing operation. It is also desireable that the automatic focalization device be suitable for miniaturizing the drive source in the camera.